Not enough information. Among other things I do in the Marine Corps, I plan emergency preparedness for a number of DOD installations all around the country. The first question you have to ask is during an emergency is do I shelter in place or evacuate? In the case of a Tsunami you will be evacuating if you are in the affected area but not caught in the initial quake (i.e. Hawaii, Guam, Okinawa during this event). What you need if you evacuate is much different than what you need if you shelter in place. If I am evacuating then I am grabbing my "Go Bag" throwing it in the back seat of my truck and I am on the road. I will have enough food, water, medical supplies, and portable shelter to get me out of dodge. I will also have a rifle with 120 rounds of ammo in magazines, a pistol with 3 spare mags, and a revolver with several spare speed strips of ammo with both .357 and snakeshot.
If I was in the immediate area affected by the earthquake and survived the initial disaster then I am probably sheltering in place. That is where stockpiles of food, water, and ammo come in. Ammo is not as important as some people seem to think it is. Unless the end of the world comes you will never need 10,000 rounds of ammo for every gun you own. No one during Katrina that I am aware of went through more than 100 rounds for neighborhood defense (not even the guy in Algiers Point who supposedly shot 60 people). I'm not saying you shouldn't have more ammo than that on you but if you are preparing to go through 500 rounds a day for a month then you would be better served double checking your preparations for food, generators, fuel, and building supplies in case you need to make hasty repairs on your house.